Sign Up to our social questions and Answers Engine to ask questions, answer people’s questions, and connect with other people.
Login to our social questions & Answers Engine to ask questions answer people’s questions & connect with other people.
Lost your password? Please enter your email address. You will receive a link and will create a new password via email.
Please briefly explain why you feel this question should be reported.
Please briefly explain why you feel this answer should be reported.
Please briefly explain why you feel this user should be reported.
How can we verify (.NET 2) if a KeyValuePair has a value assigned or not?
Dim pair as KeyValuePair(Of A, B) = Nothing
if pair.??? Then Return
As is it a structure, it can’t be verified with pair Is Nothing.
Point structure, by eg. has a p.IsEmpty verification.
Rather than using the “normal” type here – which means you can’t detect the difference between a value with the default values of
AandBas the key and value, you should use aNullable(Of KeyValuePair(Of A, B)).Effectively you’re asking exactly the same question as asking whether an
Integervariable has a value, where setting it toNothingwould give it a value of 0. How can you tell the difference between that 0 and a “real” 0? You can’t – which is whyNullable(Of T)exists in the first place. The exact same logic applies toKeyValuePair.